InDesign Color Management problem

[Razvan_Gavrila@adobeforums.com]

Hello,
I encountered a problem in InDesign CS2. I have a layout containing placed CMYK, grayscale images and spot colors. I have noticed in many forums concerning color management that InDesign can't handle grayscale images with embeded profile, it just apply them gamma 2.2 when printing or exporting to PDF. In both cases my concern is that the output files (.ps & .pdf) will not respect the corrections I made to grayscale images in Photoshop. How should I handle this files in InDesign when I will print and make proofs? Also, I have halftones and gradients from spot color. Does InDesign apply any dot gain corrections for this when printing?
Thanks

[Gerald_Singelmann@adobeforums.com]

that InDesign can't handle grayscale images with embeded profile




it handles the images well enough but it ignores the embedded profile

it just apply them gamma 2.2 when printing




this is wrong. any pixel in any greyscale image is treated exactly like an InDesign rectangle with the same value in the K-channel (leaving CMY empty). Put another way: when you have a pixel in a greyscale-image of the value 45% and place an InDesign-native vector beside it filled with 0-0-0-45 you will get exactly the same value printed.
Use the common colourmanagement controls to counter any dotgain issues.

Does InDesign apply any dot gain corrections for this when printing




Not if you do not tell it to.
When you place a greyscale-image and print/export to Document-CMYK no conversion takes place and you get exactly the values generated in Photoshop. As said: greyscale images behave exactly like CMYK-images with no embedded profile.

As an added thought: transfercurves in Photoshop EPS are ignored too. If you need correction in your images that can be undone, think about adjustment-layers in TIF or PSD.

[Razvan_Gavrila@adobeforums.com]

I have a custom grayscale profile wich I apply it to each grayscale file. It will be ignored when printing? What can I do to make InDesign to apply this profile to both raster images and gray vector images? How handle InDesign dot gain for ex. a patch of 15% black?
What about the gradients and haftones (vectors) from spot colors made in InDesign? Do this apply any dot gain for them?

[rob_day@adobeforums.com]

I have noticed in many forums concerning color management that InDesign
can't handle grayscale images with embeded profile, it just apply them
gamma 2.2 when printing or exporting to PDF.




Razvan, the 2.2 gamma is a display issue—ID displays place grayscale images as 2.2 gamma when Overpint Preview is off and uses the document's CMYK profile for the display when Overpint is on. Here the left ramps compare PS tints to identical ID tints with Preview off, the right ramps with Preview on using US Prepress Defaults as the CM setting:

<http://www.evansday.com/scripts/grayscale.jpg>

As Gerald suggests, the tint values spec'd from both ID and placed files will hold as long as you output or export to CMYK using document CMYK as the output profile. One caveat, when printing just grayscale you still need to output as CMYK. If you output to Grayscale there will be a CMYK to grayscale conversion and the values will not hold.

Rob

[Gerald_Singelmann@adobeforums.com]

Razvan, you mix concepts like dot gain and profiles and "special greyscale profile" as opposed to cmyk profile as if you did not know too much about all this colour management business.
That makes it hard to explain.